Murphy tied this week’s protest to nurses’ ongoing dispute with the company over their pension plan. At a hearing in August, nurses testified that Steward would not agree to a pension plan they had negotiated with previous owner Caritas Christi hospitals.

Murphy defended Steward nurses’ compensation packages, saying they had a contractually obligated 25-percent wage increase coming over the next four years.

“They are very well paid,” Murphy said. “The nurses in these hospitals and the MNA leadership never complain about quality unless it’s negotiation time.”

Nurses also criticized Steward’s recently announced partnership with the Compass Medical group of 90 doctors south of Boston. Compass had previously been aligned with Partners HealthCare. The move means that Compass physicians will likely refer more patients to Steward-owned hospitals rather than nonprofit hospitals, potentially disrupting the balance of competition in the industry, the nurses group said.

Attorney General Martha Coakley approved the sale of QMC to Steward with the condition that it invest up to $54 million on the facility over the next decade.